Quote Originally Posted by Fouredged Sword View Post
Titanium alloys also have the nasty side problem that they powder when they break, and in doing so cause a cloud of oxidizing metal and gas, IE a fireball. It's not a major problem with most applications because it takes a high energy hit to set off, but you don't see titanium plates in body armor for a reason.
No worse than Osmium, which, when reduced to a powder, forms Osmium Tetroxide, a highly toxic gas. Also, I'm pretty sure that Osmium is the hardest non-alloyed metal, though I haven't checked in a while.